Change GridView Column Text at runtime in ASP.Net

As I understand your question you want to replace 1 with On and 0 with Off in your gridview.

You can do it like this.

for (int i = 0; i < GridView1.Rows.Count; i++)
{
    if (GridView1.Rows[i].Cells[0].Text == "1")
        GridView1.Rows[i].Cells[0].Text = "On";
    else
        GridView1.Rows[i].Cells[0].Text = "Off";
}

If this doesnot solve your problem. please explain clearly.